FADs monitoring and tagging research

The NSW Department of Primary Industries (DPI) understand the value and importance of regular ongoing research on Fish  Aggregating Devices (FADs). DPI have implemented a monitoring program at the FADS which uses stereo video technology linked to a GPS to record the  sizes and positions of fish around the FADs. This information is vital to  understanding the size frequencies of fish that visit the FADs, as well as how the FADs are used spatially.

Catch information from recreational fishers is essential for the ongoing development and enhancement of the DPI FADs program. Recreational fishers are encouraged to participate in tagging to assist DPI in collecting data for the FADs program. Results so far have  shown that approximately 96% of FAD captures are mahi-mahi (Coryphaena hippurus). The remaining 4% consisted of a variety of pelagic fish species including striped marlin (Tetrapturus audax) and wahoo (Acanthocybium solandri).

Mahi-mahi tagging research

The DPI FADs program has resulted in mahi mahi becoming one of the most popular and reliable pelagic sportfish targeted by recreational anglers off the coast of NSW.  The yellow pelagic tag should be used to tag mahi mahi.

Tips for tagging mahi-mahi less than 6kg

Never try to tag a small mahi-mahi while the fish is in the water or dangling from a hook. Placing the fish on a piece of wet foam or sponge helps to subdue the fish considerably, reduces stress and increases post tagging survival rates. Before the fish is brought into the  boat, have a tag in the applicator, a wet towel and a measuring device ready.  Follow these simple steps:

  • Place the wet towel over the fish's eyes while it is still hanging from the hook.
  • Lay the fish on a wet, smooth, flat surface (e.g. ideally wet sponge or foam, or a wet towel will suffice) with the measuring device under or beside the fish.
  • If the hook is easily accessible, it should be removed from the fish. If the fish is hooked deeply, the leader should be cut as short as possible and the hook left in the fish.
  • Measure and record the fork length of the fish (the distance from the tip of the snout to the fork in the tail).
  • Insert the tag at about one third of the length of the fish  behind the head (the shoulder area) at a 45° angle toward the fish's head so as to have the tag angling backwards toward its tail.
  • Insert the tag deep enough so that the barb passes between the spines that radiate off the backbone. Care should be taken to insert the tag into the back muscle, below the dorsal fin, well above the spine.
  • Return the fish to the water as soon as possible.
  • The last and most important step is to record capture data on the post paid tag-return card and send it back to DPI.

Tips for tagging mahi-mahi larger than 6 kilograms

Large mahi-mahi (fish over 6 kilograms  and roughly 90 centimetres fork length) should be tagged in the water. When tagging a mahi-mahi in the water, the vessel should continue its forward motion as the fish is brought along side, helping to subdue the fish by keeping it swimming while beside the boat. Tagging should not be attempted until the fish has settled down and presents a clear, stable view of its side. Follow these simple steps:

  • Position yourself between the person holding the leader and the boats stern.
  • Insert the tag at a 45° angle toward the fish's head so as to have the tag angling backwards toward its tail.
  • Insert the tag and insure that it is firmly anchored.
  • Make sure to place the tag approximately one-third along the fish's length behind the head in the back muscle, directly below the dorsal fin  (well above the spine).
  • Before releasing the fish, get a good estimate of the fork length of the fish and/or weight. The hook should be removed if possible, otherwise, the leader should be cut as close to the hook as possible.
  • The last and most important step is to record capture data on the postage paid tag-return card and send it back to DPI.

Please note: It is very important that accurate data  on each fish is recorded on the tag-return card to maximize the value of any recaptured fish. Accurate GPS waypoints (WGS84) or the FAD you are fishing at  is critical for determining position of the first release and recapture. Please print clearly on the card.

How to get your small pelagic tags

Yellow pelagic tags and applicators can be issued to clubs or individual anglers by contacting the FADs program coordinator on (02) 4424 7423. Alternatively email gamefish.tagging@dpi.nsw.gov.au stating your name, postal address, contact phone number, number of tags you require and the location you intend to fish.